Anthropogenic Pressure on the Earth’s Climate
System
The last few decades have seen climate disruption
es, pre-eminent of which is CO
2
, mainly originating
unprecedented over the recent millennia. The trend
from burning fossil fuels. Since 1987 annual global
towards global warming is virtually certain, with 11
emissions of CO
2
have risen by about one-third.
of the 12 years to 2006 ranking among the 12
However, the per capita emissions figures clearly
warmest years since 1850, the year when systematic
illustrate large differences among regions.
temperature recording began.
The Earth’s surface temperature has increased by
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about 0.74°C since 1906 and there is a strong con-
sensus among scientists that the globally averaged
net effect of human activities since 1750 has been
one of warming. The heating up of the earth in the
last few decades has been exceptionally rapid in
comparison to the changes in climate during the past
two millennia. The Earth’s climate has now entered a
state that has no parallel in recent prehistory.
The greatest direct human pressure on the climate
system arises from the emission of greenhouse gas-
ved warming over the 20th century compared with climate model calculations
DownloaD Graphic 2
Temperature anomaly C
Temperature anomaly C
Temperature anomaly C
models using only
1.5
1.5
1.5 natural forcings
North America
Europe Asia
1.0
1.0
1.0 models using both natural
and anthropogenic forcings
0.5
0.5
0.5
observations
0
0
0
1900 1950 2000
1900 1950 2000
1900 1950 2000
Temperature anomaly C Temperature anomaly C Temperature anomaly C
1.5 1.5 1.5
Latin America Africa Australia
1.0 1.0 1.0
0.5 0.5 0.5
0 0 0
1900 1950 2000 1900 1950 2000 1900 1950 2000
Temperature anomaly C
1.5
Global Global – land Global – ocean
1.0
0.5
0
1900 1950 2000 1900 1950 2000 1900 1950 2000
Source: IPCC 2007
CLIMATE CHANGE 11